Banca de QUALIFICAÇÃO: MERY INGRID GUIMARAES DE ALENCAR

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : MERY INGRID GUIMARAES DE ALENCAR
DATA : 19/09/2019
HORA: 14:00
LOCAL: Sala de reuniões - DECOL
TÍTULO:

Interactions between floral and leaf litter and their effects on decomposition

PALAVRAS-CHAVES:

Functional diversity;non-additive effects ;functional traits ;intraspecific variation;priming effect

PÁGINAS: 40
GRANDE ÁREA: Ciências Biológicas
ÁREA: Ecologia
RESUMO:

One of the challenges of predicting the effects of diversity on ecosystem functioning is understanding the balance between the importance of various components of diversity. The theory predicts that the mechanisms determinants for non-additive effects of functional diversity on ecosystem processes can occur at both intraspecific and interspecific levels. However, the quantification of the absolute and relative effects in functional diversity on ecosystem functioning is still little explored. The spectrum of strategies used for tissue production from different organs and plant species determines intra and interspecific differences in functional attributes, such as the chemical and structural composition of these tissues. For example, chemical composition may vary between different organs of the same species (intraspecific functional diversity - DFIntra) and between the same organ or different organs of different species (interspecific functional diversity - DFInter). The afterlife effects of such functional differences in the tissues of these organs may trigger non-additive effects on the joint decomposition of these tissues. Thus, this dissertation addresses, in two chapters, the relative importance of effects of intra and interspecific litter functional diversity on the decomposition process. In the first chapter, we aim to understand, using a large number of species, the direction and magnitude of non-additive intraspecific effects from the mixture of floral and leaf litter. For this we conducted an experiment with intraspecific mixtures of floral and leaf litter from 30 species, with wide phylogenetic distribution. The interaction between floral and leaf litter generated synergistic and reciprocal effects in about 53% of treatments. Functional dissimilarity was not significantly related to the occurrence and magnitude of nonadditive effects (F = 0.0654; p = 0.8074). In addition, on average, and contrary to expectations, floral decay decomposition responded positively to the mixture while leaf litter responded negatively to the mixture. For the second chapter we aimed to evaluate the relative effect of intra and interspecific variation and their interactions on the magnitude of decomposition. For this we used an experimental approach with floral and leaf litter of three species decomposing separately and together in all pairs of possible combinations both intra and interspecific. By manipulating differences between floral and leaf litter we use a set of models that explicitly considers the role of species and functional differences between littr types, for model selection we use the AIC criterion. We quantified 18 attributes related to the chemical and structural composition of the litter to analyze the effects of the functional dissimilarity of the mixtures on possible nonadditive effects of decomposition. As expected, floral had on average higher decomposition rate compared to leaf litter (F = 197.4, p <0.0001). The models indicated non-additive effects of litter diversity on decomposition (ΔAIC = 0, R² = 0.97, p <0.0001), which were mostly synergistic (i.e. accelerated decomposition) and stronger in mixtures of floral and leaf litter from different species. However, despite the widespread occurrence of non-additive effects, we found no relationship these with functional dissimilarity (F = 1,343; p = 0.2676).  These results suggest that the intra and interspecific interaction between floral and leaf litter generates non-additive effects on decomposition, but without association with functional dissimilarity. The results of this dissertation show the importance of intra and interspecific interaction of litter from different plant organs in the mediation of the decomposition process. Such results should be incorporated into the knowledge about littr diversity in decomposition, since it shows that diversity effects can be triggered both intra and interspecifically.

MEMBROS DA BANCA:
Presidente - 1714892 - ADRIANO CALIMAN FERREIRA DA SILVA
Externo à Instituição - RAFAEL DETTOGNI GUARIENTO
Interna - 3058386 - VANESSA GRAZIELE STAGGEMEIER